Along the last years, we have witnessed the growing demand for services, applications, and systems that depend on the specific location of both people and a variety of things and gadgets. Currently, the Global Positioning System (GPS) offers good accuracy on-location services around the world. Nevertheless, it does not work efficiently on applications that require several small, cheap, and low power devices. Under such conditions, researchers prefer to work with low-cost wireless alternatives such as WiFi, Zigbee, LoRa, Sigfox, among others. The purpose of this work is twofold. Firstly we evaluate the time-measurement and radio frequency capabilities of Pycom LoRa hardware implementation, in order to develop a low-cost and GPS-independent positioning system. Then, with these results, we propose and evaluate a positioning system with LoRa technology and based on the received signal strength indicator. Extensive field test measurements in outdoor rural environments show that we can obtain position estimation errors lesser than around 7% of the maximum distance between anchor nodes.

在过去的几年中，我们目睹了对服务，应用程序和系统的不断增长的需求，这些需求取决于人和各种事物和小工具的特定位置。当前，全球定位系统（GPS）在全球范围内提供良好的精确定位服务。但是，它在需要多个小型，廉价和低功耗设备的应用程序中无法有效工作。在这种情况下，研究人员更喜欢使用低成本无线替代方案，例如WiFi，Zigbee，LoRa，Sigfox等。这项工作的目的是双重的。首先，我们评估Pycom LoRa硬件实现的时间测量和射频功能，以开发一种低成本且独立于GPS的定位系统。然后，有了这些结果，我们基于接收到的信号强度指示器，提出并评估了采用LoRa技术的定位系统。在室外农村环境中进行的大量现场测试测量表明，我们可以获得的位置估计误差小于锚点之间最大距离的7％左右。